US10254542B2 - Holographic projector for a waveguide display - Google Patents

Abstract

Examples are disclosed that relate to a near-eye display device including a holographic display system. The holographic display system includes a light source configured to emit light that is converging or diverging, a waveguide configured to be positioned in a field of view of a user's eye, and a digital dynamic hologram configured to receive the light, and project the light into the waveguide such that the light propagates through the waveguide.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 62/416,094, filed Nov. 1, 2016, the entirety of which is hereby incorporated herein by reference.

BACKGROUND

A near-eye display device may utilize a waveguide to deliver an image from an image producing element to a user's eye for viewing.

SUMMARY

Examples are disclosed that relate to a near-eye display device including a holographic display system. The holographic display system includes a light source configured to emit light that is converging or diverging, a waveguide configured to be positioned in a field of view of a user's eye, and a digital dynamic hologram configured to receive the light, and project the light into the waveguide such that the light propagates through the waveguide.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example near-eye display device.

FIGS. 2-9 show example holographic display systems that may be implemented in a near-eye display device.

FIG. 10 shows an example computing system.

DETAILED DESCRIPTION

In a near-eye display device including a waveguide to direct an image to a user's eye, various different approaches may be used to direct the image to the entrance of the waveguide. In some examples, a light engine (e.g., a projector) that includes a micro-display is used in conjunction with collimating and imaging optics to direct the image to the entrance of the waveguide. However, the light engine has limitations in terms of size and/or resolution. As such, while the waveguide may be able to support high resolution imagery while having a compact form factor, the inherent properties of the light engine may prevent reduction of a form factor of the near-eye display device. As a more specific example, because of the finite size of the micro-display, relay optics used to direct the image from the micro-display to the waveguide may occupy a substantial amount of space, in both length and diameter, as the relay optics would be spaced apart from the micro-display in order to collect a cone of light emitted from the pixels of the micro-display. Moreover, reducing the size of the display area does not reduce the size of the relay optics. As pixels get smaller, they emit over a larger cone of angles. Thus, the diameter of the lens (i.e. numerical aperture (NA)) would increase. Therefore, given a minimum pixel size of many micrometers (diameter or diagonal size) for the device, and a maximum size of the light engine, there is an upper limit on image quality.

Accordingly, examples are disclosed that relate to a near-eye display device including a holographic display system configured to direct an image to a waveguide. As described in more detail below, the holographic display system includes a Digital Dynamic Hologram (DDH) illuminated by a diverging or converging beam to form an image at the waveguide.

By using a DDH for image formation instead of a micro-display, there is no need for additional relay optics between the DDH and the entrance of the waveguide. In addition, the DDH may be large in size, which helps to decrease aperture diffraction, and thus improve image quality. Moreover, such a configuration may be optically efficient relative to other configurations that use a micro-display, as light is primarily steered rather than attenuated to form the image. Further, aberrations in any optical components may be corrected by the DDH. Additionally, the pixels in the DDH can be as small as desired, as diffractive effects are used to form the image. In other words, there is no minimum pixel size requirement in order to achieve a desired resolution.

Furthermore, by illuminating the DDH with a diverging or converging beam, a Field of View (FOV) of the near-eye display device may be increased relative to other configurations that include an illumination source configured to emit a collimated beam. In addition, different parts of the DDH create different parts of the image. Thus, a waveguide coupling hologram (WGCH) positioned at the entrance of the waveguide can be configured spatially to accept only the narrow range of angles that correspond to the DDH. Since the WGCH always operates at its configured incident angle, light propagation efficiency is increased such that more light is coupled into the waveguide relative to other configurations that do not employ a DDH.

The above described features may enable a near-eye display device having such features to have reduction in weight and size relative to a near-eye display device that employs a light projection engine.

In some implementations, the near-eye display device may include a low resolution amplitude display (LRAD) upstream or downstream of the DDH. As a phase hologram does not absorb light, it can form an image but may not reduce a mean value of the intensity. The LRAD removes this issue by modulating locally the intensity of the light. For example, the pixel size of the LRAD could be 10 to 100 times larger than the DDH pixel size (e.g., 100's of μm). In such examples, the LRAD may be configured to not reduce the aperture size of the DDH. In one example, the pixels of the LRAD are grouped together in areas of ˜1 mm²so the aperture size formed by the LRAD is sufficiently large so the aperture diffraction is sufficiently small to be below the human eye's acuity. Note that if higher resolutions are required, then the pixels of the LRAD can be arranged in groups that occupy larger areas. Although the LRAD is shown in the holographic display systems ofFIGS. 2-9 as being intermediate the waveguide and the DDH, it will be appreciated that the LRAD may be arranged in other locations in the holographic display systems.

In some implementations, the near-eye display device may include a fixed aperture mask (FAM) at an appropriate plane for blocking, redirecting, or otherwise inhibiting unwanted light from being coupled into the waveguide. For example, zero order and/or higher order light may be blocked by the FAM. In such a configuration, the FAM may be spaced apart an appropriate distance from the DDH so that the unwanted light is concentrated (i.e. focused) on the mask while the desired image is minimally affected. Non-limiting examples of the FAM include an amplitude mask that absorbs light, a diffraction grating or other diffractive element that directs light out of the holographic display system, and a transparent interface through which light passes unaffected on the other side of the waveguide.

FIG. 1 shows an example near-eye display device100. Thedisplay device100 includes right-eye and left-eyeholographic display systems102R and102L mounted to aframe104 configured to rest on a wearer's head. Each of the right-eye and left-eye holographic display systems102 include image display componentry configured to project computerized virtual imagery into left andright display windows106R and106L in the wearer's field of view (FOV). In one example, the light-deflecting image display componentry includes one or more holographic optical components. Different example holographic display systems representative of the right-eye and left-eyeholographic display systems102R and102L are described in more detail below with reference toFIGS. 2-7.

In some implementations, the right andleft display windows106R and106L are wholly or partially transparent from the perspective of the wearer, to give the wearer a view of a surrounding environment. In other implementations, the right and left display windows106R,106L are opaque, such that the wearer is completely absorbed in the virtual-reality (VR) imagery provided via the near-eye display device. In yet other implementations, the opacities of the right and/orleft display windows106R,106L may be controllable dynamically via a dimming filter. A substantially see-through display window, accordingly, may be switched to full opacity for a fully immersive virtual-reality experience.

Display device100 includes an on-board computing system108 configured to render the computerized display imagery, which is provided to right and left display windows106 via right-eye and left-eye holographic display systems102.Computing system108 is configured to send appropriate control signals toright display window106R that cause the right display window to form a right display image. Likewise, thecomputing system108 is configured to send appropriate control signals toleft display window106L that cause the left display window to form a left display image. The wearer of thedisplay device100 views the right and left display images with right and left eyes, respectively. When the right and left display images are presented in an appropriate manner, the wearer experiences the perception of virtual imagery—i.e., one or more virtual objects at specified positions, and having specified 3D content and other display properties. Such virtual imagery may have any desired complexity; it may, for example, comprise a totally virtual scene having both foreground and background portions, or one of foreground and background to the exclusion of the other. Thecomputing system108 may include a logic subsystem and a storage subsystem, as discussed in more detail below with respect toFIG. 10. Operation of thedisplay device100 is additionally or alternatively controlled by one or more computing devices remote from thedisplay device100 in communication with thedisplay device100, represented schematically as remote computing device116.

Thecomputing system108 is in communication with various sensors and vision system components of thedisplay device100 to provide information to thecomputing system108. Such sensors may include, but are not limited to, position-sensingcomponentry110, a world-facingvision system112, and a wearer-facingvision system114. The position-sensingcomponentry110 is usable by thecomputing system108 to determine the position and orientation of thedisplay device100 in a selected frame of reference. In some implementations, the position-sensingcomponentry110 provides a six degrees-of-freedom (6DOF) estimate of the three Cartesian coordinates of the display system plus a rotation about each of the three Cartesian axes. To this end, the position-sensingcomponentry110 may include any, some, or each of an accelerometer, gyroscope, magnetometer, and global-positioning system (GPS) receiver. The output of the position-sensingcomponentry110 is used to map the position, size, and orientation of virtual display objects onto the right and left display windows106.

The world-facingmachine vision system112 may include one or more of a color or monochrome flat-imaging camera, a depth-imaging camera, and an infrared projector. The term ‘camera’ refers herein to any machine-vision component configured to image a scene or subject. The depth-imaging camera may be configured to acquire a time-resolved sequence of depth maps of a scene or subject. In some examples, discrete flat-imaging and depth-imaging cameras may be arranged with parallel optical axes oriented in the same direction. Further, in some examples, image or video output from the flat-imaging and depth-imaging cameras may be co-registered and combined into a unitary (e.g., RGB+depth) data structure or stream. In examples in which depth-imaging camera is a suitably configured time-of-flight depth-imaging camera, a data stream representing both depth and brightness (e.g., IR+depth) may be available by combining outputs differing in phase. The infrared projector, where included, may be configured to emit infrared alignment light to the physical space. The infrared alignment light may be reflected from the physical space back to thedisplay device100 and imaged by a camera of each of the left-eye and right-eyeoptical systems102R and102L.

In some implementations, thedisplay device100 may include a wearer-facingmachine vision system114. The wearer-facingmachine vision system114 may include a color or monochrome flat-imaging camera, a depth-imaging camera, and/or an infrared projector. The wearer-facingvision system114 is configured to measure attributes of a wearer ofdisplay device100. In some examples, such attribute data is used by computingsystem108 to calibrate the left-eyeoptical system102L with the right-eyeoptical system102R, as well as to determine a position of the wearer's eye(s), a gaze vector, a gaze target, a pupil position, head orientation, eye gaze velocity, eye gaze acceleration, change in angle of eye gaze direction, and/or any other suitable eye tracking information.

FIGS. 2-7 show different example holographic display systems in simplified form. For example, such holographic display systems may be implemented in a computing system in the form of the example near-eye display device100 ofFIG. 1 as well as theexample computing system1000 ofFIG. 10. The holographic display systems described herein may include a pupil replicating waveguide assembly including a waveguide (WG), a waveguide coupling hologram (WGCH), and one or more pupil replicating holograms (PRH), as example components.

The term hologram may have different meanings. A hologram may be a simple or very complex structure in one-dimension, two-dimensions or even three-dimensions. The hologram may modulate phase, amplitude, or both. The term hologram and grating may be interchangeable in some cases. As used herein, the image forming hologram will be referred to as a Digital Dynamic Hologram (DDH).

The WG can be either flat or curved. When curved, a suitable adjustment may be made to the PRH to compensate for the curvature. Variable thickness waveguides are possible. For simplicity, the WG is depicted as flat, but the description herein also applies to a curved waveguide. The WG may be made from any suitable materials, including glass or plastic materials. In addition, the PRH may be eliminated or replaced with other optical elements that extract light out of the waveguide. Such optical elements may not necessarily replicate the pupil. Non-limiting examples of such optical elements include a volume hologram, a turning film, and combinations thereof.

The WGCH accepts light from the outside and diffracts the light into the WG at a sufficiently large angle so that the light is trapped in the waveguide due to total internal reflection (TIR). Note that other techniques can be used to launch the beam into the WG, such as a prism or a Fresnel prism. Further, such components can be embedded in the WG, rather than located on a surface of the WG. Additionally, other mechanisms may be used to launch light into the WG, alternatively to or in addition to the WGCH.

Once the light beam enters the WG, the light beam propagates through the WG until it hits the PRH. At the PRH, the light beam splits into two beams with the first light beam exiting the WG and being directed to the user's eye and the second light beam continuing on a path through the WG. The light beam continues down the WG and may be again split into the PRH. The angular distribution of rays at the user's eye is the same as at the entrance of the waveguide assembly where the light beam enters the WGCH. This angular distribution of rays at the two holograms, i.e. at the entrance of the WGCH and the exit of the PRH is related to the Fourier transform of the image, or is in Fourier space as compared with the image space focused by the user's eye. Note that the PRH may include more than one hologram. For example, the PRH may include a horizontal hologram and a vertical hologram that may cooperatively replicate a pupil.

FIG. 2 shows an exampleholographic display system200 that includes a pupil replicating waveguide (WG)202, aDDH204 illuminated with diverging light, anLRAD206. Light diverging from asource207 illuminates a phase (or amplitude) modulating device in the form of theDDH204. TheDDH204 can be an appropriately configured LCD, LCoS, or other phase (or amplitude) modulating device. In some implementations, the DDH may be transmissive. In other implementations, the DDH may be reflective. TheDDH204 deflects the light by a small angle (e.g., a few degrees) to form a small part of the image by moving light in the vicinity of this small part. As light is not absorbed by theDDH204, the LRAD may be used to absorb some light to lower the mean intensity to a target level. Once light is coupled into theWG202 via aWGCH208, the small pupil formed by theDDH204 is replicated by aPRH210 of theWG202, effectively expanding the eye boxes. TheDDH204 may be configured to receive the diverging light and modulate the diverging light for collimation and coupling byWGCH208 into theWG202 such that the light propagates through the waveguide to form an image in a user's eye.

In such a configuration, alarger WGCH208 may be used to couple the diverging light into theWG202 relative to a configuration in which the illumination light is converging. By using alarger WGCH208 having more regions, each region may be required to support a smaller angular range of total bandwidth of the illumination light. Further, the diffraction efficiency of each region may be tuned to the smaller angular range to improve the coupling efficiency of the region.

In the depicted example, theDDH204, theWG202 and theWGCH208 are shown as being parallel to one another. In other examples, the different components may be arranged at other angles relative to one another. Further, in other examples, a reflective DDH and a beam splitter may be used in place of thetransmissive DDH204 ofFIG. 2.

FIG. 3 shows another exampleholographic display system300 that includes apupil replicating waveguide302, aWGCH303, aDDH304 illuminated with converging light, and anLRAD306. An example light source is depicted schematically asoptics307 configured to form converging light.Optics307 may comprise any suitable components for forming converging light to provide toDDH304.

In this example, some distance may exist between theDDH304 and theWGCH303. As such, the entrance pupil diameter decreases, which may allow a size of theWGCH303 to be reduced relative to a configuration in which the illumination light is diverging. Such a reduction in size of theWGCH303 may help to reduce a form factor of the holographic display system. Alternatively, theDDH304, theLRAD306 and theWGCH303 can be at very close proximity or in contact. Such a configuration may utilize aWGCH303 with area comparable to the area of theDDH304 and having a thin form factor.

FIG. 4 shows another exampleholographic display system400. Thesystem400 ofFIG. 4 is similar to the arrangement ofFIG. 3, but is configured to generate an image via reflection. As such, theDDH404 is reflective and illuminated by converging light that is directed through theWG402,WGCH403 andLRAD407 prior to being reflected by theDDH404 back to theWGCH403. The illumination light may be directed at theDDH404 byoptics409 positioned on the opposite side of theWG402 from theDDH404. In this configuration, theWGCH403 can be configured to operate only at a certain input angle range. Since incident and reflected angles are different for most positions on theDDH404, theWGCH403 thus may be configured to couple only the reflected light into theWG402. In such an example, normal incident rays have identical input and output angles. Thus, to avoid coupling the normal incident rays into theWG402, theDDH404 may be arranged at a sufficiently large angle so all incident and reflected rays face theWGCH403 at different angles. In some implementations, theDDH404 may be illuminated in reflection mode on the same side of the WG402 (e.g., with one or more of folding and off-axis optics) instead of from the opposing side of theWG402. Examples of such configurations are discussed in further detail below with reference toFIGS. 8 and 9.

The configuration ofFIG. 4 may offer various advantages. For example, areflective DDH404 may have higher efficiency relative to a transmissive DDH. Further, thereflective DDH404 may have a higher fill factor (active area/unactive area) relative to a transmissive DDH, which produces less energy in the higher orders. Also, because light passes through thereflective DDH404 twice, the DDH may have a thinner phase modulating layer relative to a transmissive DDH, which results in the reflective DDH operating faster than a transmissive DDH. In implementations where light passes through the LRAD twice, both passes may be taken into consideration when computing the phase profile on the DDH and the amplitude profile on the LRAD.

FIG. 5 shows another exampleholographic display system500 utilizing areflective DDH504 and apupil replicating WG502. InFIG. 5, thereflective DDH504 is illuminated using a Front Light Waveguide (FLWG)506. TheFLWG506 has an input coupling hologram (FLCH)508 to introduce rays fromlight source optics507 into the waveguide. The light input into the waveguide may comprise a converging, diverging or collimated beam of rays. The FLWG also comprises a second hologram as an output coupling. In some examples, the output coupling hologram may take the form of an angularly selective hologram, such as a volume hologram (Front Light Volume Hologram (FLVH))510. TheFLVH510 diffracts light out of the waveguide at certain angles and forms a converging or diverging beam similar to one formed by a refractive lens. An advantage of using a second waveguide for front illuminating the device is that the device can be more compact, as the optics for making a diverging/converging source are embedded in theFLWG506.System500 also comprises aLRAD512, and aWGCH514 to couple light intoWG502.

In configurations that include aFLWG506, different approaches may be employed to avoid having light coupled back into theFLWG506 after reflection from theDDH504. As one example, an off-axis holographic relay folded into theFLWG506 may be employed to couple diverging or converging light into theWG502. The holographic relay does not replicate the light rays. Instead, the rays enter into theFLWG506, via a coupling hologram or a prism for example, and travel until they hit a surface where the Bragg condition is met (k_in−k_out=k_grating). By recording an appropriate volume hologram on top of theFLWG506, the assembly acts as a flat magnifying lens, allowing rays to exit at a desired position and allowing converging or diverging illumination to be formed.

In another example, a collimated beam (i.e., single input angle) enters theWG502 via a first diffractive optical element (DOE) such as a coupling hologram, and a second DOE, such as a Surface Relief Grating (SRG), in the waveguide replicates the beam into the X direction. A third DOE, such as an SRG, is positioned on the exit of the WG to direct at least some light exiting the waveguide towards the user's eye with every incident bounce. The efficiency of the third DOE may be configured to be low to avoid having substantially all light exit after a low number of bounces. Because the efficiency of the third DOE is low, the reflected light from the DDH is not affected significantly.

FIG. 6 shows another exampleholographic display system600. The example ofFIG. 6 is similar to the system ofFIG. 4, except that the WGCH comprises a polarization-sensitive hologram602. In the illustrated example, the polarization-sensitive hologram602 is a polarization grating (PG)602. ThePG602 can be configured to diffract circularly polarized light in different directions depending whether it is Left Hand Circularly Polarized (LHCP) or Right Hand Circularly Polarized (RHCP). In one simple example form, thePG602 will diffract LHCP light but leave RHCP light unaffected. Further, the holographic display system includes awaveplate606 positioned between theDDH604 and thePG602. For simplicity, a single ray is shown. Assuming thePG602 is configured to ignore LHCP light, incoming light that is LHCP is not affected by thePG602 and passes through thePG602. The waveplate606 changes the polarization from circular to linear for phase modulation by theDDH604. The reflected rays then pass through the waveplate, which converts the linearly polarized light to RHCP. The RHCP is then diffracted by thePG602 by a suitable angle to couple into theWG608. In other implementations, a polarization selective diffractive element other than a polarization grating may be used in the holographic display system instead.

FIG. 7 shows aholographic projection system700 in which a fixed aperture mask (FAM)702 is utilized in a similar manner as inFIG. 2. Converging rays emerging from theDDH704 will converge into a small aperture; as such, theFAM702 may be placed in a plane encompassing that aperture. Undiffracted rays will be tightly focused to a single point, such that theFAM702 may block the rays or divert the rays out of the waveguide. TheFAM702 may also be configured to block or divert rays corresponding to the higher orders of theDDH704. Thus, theFAM702 may be configured to pass only a selected order (or selected orders) of light from theDDH704, and to selectively block other orders. In such an example, a distance between theFAM702 and theWGCH706 may be zero, thereby allowing the formation of a spatially compact system. In this case, the FAM may rely on the angular selectivity of a volume hologram to redirect the unwanted light, rather than use an attenuating mask element. TheFAM702 may be positioned on either side of theWG708, or incorporated into theWGCH706, depending upon a location at which the rays converge. Further, theWGCH706 may contain a different hologram, or no hologram at all at the location where theFAM702 would absorb or deflect the beam. This effectively helps to avoid coupling the unwanted light into theWG708.

FIG. 8 shows another exampleholographic display system800 that is configured to generate an image via reflection through folding optics.Optics809 provide converging light (e.g., from an off-axis light source) tofolding optics808. In one example, thefolding optics808 include a beam splitter. The beam splitter is configured to “fold” or direct the converging light towards theDDH804. TheDDH804 is configured to direct the converging light through theLRAD807, theWGCH803, and into theWG802. In this configuration, theDDH804 is positioned on a same side of theWG802 as the light source/optics809.

FIG. 9 shows another exampleholographic display system900 that is configured to generate an image via reflection from an off-axis light source. In particular,optics908 provide diverging light (e.g., from an off-axis light source) to theDDH904. TheDDH904 is configured to direct the diverging light through theLRAD907, theWGCH903, and into theWG902. In this configuration, theDDH904 is positioned on a same side of theWG802 as the light source/optics908.

The above described holographic display systems are provided as examples, and other configurations in which a DDH directs diverging or converging light into a WG may be contemplated.

FIG. 10 schematically shows a non-limiting implementation of acomputing system1000 in simplified form.Computing system1000 may take the form of one or more personal computers, server computers, tablet computers, home-entertainment computers, network computing devices, gaming devices, mobile computing devices, mobile communication devices (e.g., smart phone), virtual-reality devices, and/or other computing devices. For example, thecomputing system1000 may be a non-limiting example of thecomputing system108 of thedisplay device100 ofFIG. 1.

Computing system1000 includes alogic machine1002 and astorage machine1004.Computing system1000 may optionally include adisplay subsystem1006,input subsystem1008,communication subsystem1010, and/or other components not shown inFIG. 10.

Logic machine1002 includes one or more physical devices configured to execute instructions. For example, thelogic machine1002 may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical constructs. Such instructions may be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.

Thelogic machine1002 may include one or more processors configured to execute software instructions. Additionally or alternatively, thelogic machine1002 may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. Processors of thelogic machine1002 may be single-core or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and/or distributed processing. Individual components of thelogic machine1002 optionally may be distributed among two or more separate devices, which may be remotely located and/or configured for coordinated processing. Aspects of thelogic machine1002 may be virtualized and executed by remotely accessible, networked computing devices configured in a cloud-computing configuration.

Storage machine1004 includes one or more physical devices configured to hold instructions executable by thelogic machine1002 to implement the methods and processes described herein. When such methods and processes are implemented, the state ofstorage machine1004 may be transformed—e.g., to hold different data.

Storage machine1004 may include removable and/or built-in devices.Storage machine1004 may include optical memory (e.g., CD, DVD, HD-DVD, Blu-Ray Disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and/or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tape drive, MRAM, etc.), among others.Storage machine1004 may include volatile, nonvolatile, dynamic, static, read/write, read-only, random-access, sequential-access, location-addressable, file-addressable, and/or content-addressable devices.

It will be appreciated thatstorage machine1004 includes one or more physical devices. However, aspects of the instructions described herein alternatively may be propagated by a communication medium (e.g., an electromagnetic signal, an optical signal, etc.) that is not held by a physical device for a finite duration.

Aspects oflogic machine1002 andstorage machine1004 may be integrated together into one or more hardware-logic components. Such hardware-logic components may include field-programmable gate arrays (FPGAs), program- and application-specific integrated circuits (PASIC/ASICs), program- and application-specific standard products (PSSP/ASSPs), system-on-a-chip (SOC), and complex programmable logic devices (CPLDs), for example.

When included,display subsystem1006 may be used to present a visual representation of data held bystorage machine1004. This visual representation may take the form of a graphical user interface (GUI). As the herein described methods and processes change the data held by the storage machine, and thus transform the state of the storage machine, the state ofdisplay subsystem1006 may likewise be transformed to visually represent changes in the underlying data.Display subsystem1006 may include one or more display devices utilizing virtually any type of technology. Such display devices may be combined withlogic machine1002 and/orstorage machine1004 in a shared enclosure, or such display devices may be peripheral display devices. As a non-limiting example,display subsystem1006 may include the near-eye displays described above.

When included,input subsystem1008 may comprise or interface with one or more user-input devices such as a keyboard, mouse, touch screen, or game controller. In some implementations, the input subsystem may comprise or interface with selected natural user input (NUI) componentry. Such componentry may be integrated or peripheral, and the transduction and/or processing of input actions may be handled on- or off-board. Example NUI componentry may include a microphone for speech and/or voice recognition; an infrared, color, stereoscopic, and/or depth camera for machine vision and/or gesture recognition; a head tracker, eye tracker, accelerometer, and/or gyroscope for motion detection and/or intent recognition; as well as electric-field sensing componentry for assessing brain activity.

When included,communication subsystem1010 may be configured to communicatively couplecomputing system1000 with one or more other computing devices.Communication subsystem1010 may include wired and/or wireless communication devices compatible with one or more different communication protocols. As non-limiting examples, the communication subsystem may be configured for communication via a wireless telephone network, or a wired or wireless local- or wide-area network. In some implementations, thecommunication subsystem1010 may allowcomputing system1000 to send and/or receive messages to and/or from other devices via a network such as the Internet.

In an example, a near-eye display device, comprises a holographic display system comprising a light source configured to emit light that is converging or diverging, a waveguide configured to be positioned in a field of view of a user's eye, and a digital dynamic hologram configured to receive the light and spatially modulate the light for coupling into the waveguide such that the light propagates through the waveguide. In this example and/or other examples, the digital dynamic hologram may be positioned intermediate the light source and the waveguide, and the digital dynamic hologram may be configured to receive converging light from the light source. In this example and/or other examples, the near-eye display device may further comprise a fixed aperture mask configured to block one or more orders of the converging light from entering the waveguide. In this example and/or other examples, the digital dynamic hologram may be positioned intermediate the light source and the waveguide, and wherein the digital dynamic hologram is configured to receive diverging light. In this example and/or other examples, the dynamic digital hologram may be configured to reflect the light toward a waveguide coupling hologram for coupling light into the waveguide. In this example and/or other examples, the digital dynamic hologram may be positioned on an opposite side of the waveguide from the light source, the light may travel from the light source through the waveguide to the digital dynamic hologram, and the digital dynamic hologram may reflect the light back toward the waveguide for coupling into the waveguide. In this example and/or other examples, the near-eye display device may further comprise a waveguide coupling hologram configured to transmit light from the light source received from the light source directed toward the digital dynamic hologram, and to couple light received from the digital dynamic hologram into the waveguide. In this example and/or other examples, the near-eye display device may further comprise a polarization-sensitive hologram positioned between the waveguide and the digital dynamic hologram and configured to diffract light polarized in a first circular direction and transmit light polarized in a second circular direction, a waveplate positioned intermediate the digital dynamic hologram and the polarization-sensitive hologram and configured to receive the light polarized in the second circular direction, change the light from being polarized in the second circular direction to being linearly polarized, and direct the linearly polarized light to the digital dynamic hologram, wherein the digital dynamic hologram is configured to reflect the linearly polarized light back to the waveplate to change the reflected light from being linearly polarized to polarized in the first circular direction for diffraction by the polarization-sensitive hologram into the waveguide. In this example and/or other examples, the digital dynamic hologram may be positioned on a same side of the waveguide as the light source, the light may be directed via one or more of folding optics and off-axis optics toward the digital dynamic hologram, and the digital dynamic hologram may reflect the light toward the waveguide for coupling into the waveguide. In this example and/or other examples, the near-eye display device may further comprise a front light waveguide positioned intermediate the digital dynamic hologram and the waveguide, a front light input coupling hologram configured to receive the light and direct the light into the front light waveguide, a front light output coupling hologram configured to direct the light exiting the front light waveguide to the digital dynamic hologram and make the light converging or diverging, and a pupil-replicating waveguide configured to receive light reflected by the digital dynamic hologram and direct the received light toward the user's eye. In this example and/or other examples, the front light output coupling hologram may comprise a volume hologram. In this example and/or other examples, the near-eye display device may further comprise an amplitude display positioned between the digital dynamic hologram and the waveguide. In this example and/or other examples, may further comprise one or more pupil-replicating holograms coupled with the waveguide that forms a replicated exit pupil.

In an example, a near-eye display device comprises a holographic display system comprising a waveguide configured to be positioned in a field of view of a user's eye, a digital dynamic hologram configured to receive light from a light source, modulate the light, and direct the light toward the waveguide for coupling into the waveguide such that the light propagates through the waveguide toward the user's eye, a front light waveguide positioned intermediate the digital dynamic hologram and the waveguide, a front light input coupling hologram configured to receive the light from the light source and couple the light into the front light waveguide, and a front light output hologram configured to couple light out of the front light waveguide to the digital dynamic hologram and make the light converging or diverging. In this example and/or other examples, the light source may be configured to provide collimated light to the front light input coupling hologram. In this example and/or other examples, the light source may be configured to provide converging light or diverging light to the front light input coupling hologram. In this example and/or other examples, the near-eye display device may further comprise an amplitude display positioned between the digital dynamic hologram and the waveguide coupling hologram.

In an example, a near-eye display device comprises a holographic display system comprising a light source comprising optics configured to output converging light, a waveguide positioned in a field of view of a user's eye, a digital dynamic hologram configured to receive the converging light and spatially modulate the converging light for coupling into the waveguide such that the light propagates through the waveguide to form an image in the user's eye, and a fixed aperture mask positioned between the digital dynamic hologram and the waveguide and configured to block converging light from the light source that is not diffracted by the digital dynamic hologram. In this example and/or other examples, the near-eye display device may further comprise a pupil replicating hologram coupled with the waveguide and configured to receive light reflected by the digital dynamic hologram and direct the received light toward the user's eye. In this example and/or other examples, the fixed aperture mask may be further configured to block one or more orders of diffracted light received from the digital dynamic hologram.

It will be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various acts illustrated and/or described may be performed in the sequence illustrated and/or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes may be changed.

The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.

Claims (20)

The invention claimed is:

1. A near-eye display device, comprising:

a holographic display system comprising:

a light source configured to emit light that is converging or diverging;

a waveguide configured to be positioned in a field of view of a user's eye; and

a digital dynamic hologram configured to receive the light that is converging or diverging and spatially modulate the light to form an image for coupling into the waveguide such that the light propagates through the waveguide.

2. The near-eye display device ofclaim 1, wherein the digital dynamic hologram is positioned intermediate the light source and the waveguide, and wherein the digital dynamic hologram is configured to receive converging light from the light source.

3. The near-eye display device ofclaim 2, further comprising a fixed aperture mask configured to block one or more orders of the converging light from entering the waveguide.

4. The near-eye display device ofclaim 1, wherein the digital dynamic hologram is positioned intermediate the light source and the waveguide, and wherein the digital dynamic hologram is configured to receive diverging light.

5. The near-eye display device ofclaim 1, wherein the dynamic digital hologram is configured to reflect the light toward a waveguide coupling hologram for coupling light into the waveguide.

6. The near-eye display device ofclaim 5, wherein the digital dynamic hologram is positioned on an opposite side of the waveguide from the light source, wherein the light travels from the light source through the waveguide to the digital dynamic hologram, and wherein the digital dynamic hologram reflects the light back toward the waveguide for coupling into the waveguide.

7. The near-eye display device ofclaim 6, further comprising a waveguide coupling hologram configured to transmit light from the light source received from the light source directed toward the digital dynamic hologram, and to couple light received from the digital dynamic hologram into the waveguide.

8. The near-eye display device ofclaim 6, further comprising:

a polarization-sensitive hologram positioned between the waveguide and the digital dynamic hologram and configured to diffract light polarized in a first circular direction and transmit light polarized in a second circular direction;

a waveplate positioned intermediate the digital dynamic hologram and the polarization-sensitive hologram and configured to receive the light polarized in the second circular direction, change the light from being polarized in the second circular direction to being linearly polarized, and direct the linearly polarized light to the digital dynamic hologram, wherein the digital dynamic hologram is configured to reflect the linearly polarized light back to the waveplate to change the reflected light from being linearly polarized to polarized in the first circular direction for diffraction by the polarization-sensitive hologram into the waveguide.

9. The near-eye display device ofclaim 5, wherein the digital dynamic hologram is positioned on a same side of the waveguide as the light source, wherein the light is directed via one or more of folding optics and off-axis optics toward the digital dynamic hologram, and wherein the digital dynamic hologram reflects the light toward the waveguide for coupling into the waveguide.

10. The near-eye display device ofclaim 5, further comprising:

a front light waveguide positioned intermediate the digital dynamic hologram and the waveguide;

a front light input coupling hologram configured to receive the light and direct the light into the front light waveguide;

a front light output coupling hologram configured to direct the light exiting the front light waveguide to the digital dynamic hologram and make the light converging or diverging; and

a pupil-replicating waveguide configured to receive light reflected by the digital dynamic hologram and direct the received light toward the user's eye.

11. The near-eye display device ofclaim 10, wherein the front light output coupling hologram comprises a volume hologram.

12. The near-eye display device ofclaim 1, further comprising an amplitude display positioned between the digital dynamic hologram and the waveguide.

13. The near-eye display device ofclaim 1, further comprising one or more pupil-replicating holograms coupled with the waveguide that forms a replicated exit pupil.

14. A near-eye display device, comprising:

a holographic display system comprising:

a waveguide configured to be positioned in a field of view of a user's eye;

a digital dynamic hologram configured to receive light from a light source, spatially modulate the light to form an image, and direct the light toward the waveguide for coupling into the waveguide such that the light propagates through the waveguide toward the user's eye;

a front light waveguide positioned intermediate the digital dynamic hologram and the waveguide;

a front light input coupling hologram configured to receive the light from the light source and couple the light into the front light waveguide; and

a front light output hologram configured to couple light out of the front light waveguide to the digital dynamic hologram and make the light converging or diverging.

15. The near-eye display device ofclaim 14, wherein the light source is configured to provide collimated light to the front light input coupling hologram.

16. The near-eye display device ofclaim 14, wherein the light source is configured to provide converging light or diverging light to the front light input coupling hologram.

17. The near-eye display device ofclaim 14, further comprising an amplitude display positioned between the digital dynamic hologram and the waveguide coupling hologram.

18. A near-eye display device, comprising:

a holographic display system comprising:

a light source comprising optics configured to output converging light;

a waveguide positioned in a field of view of a user's eye;

a digital dynamic hologram configured to receive the converging light and spatially modulate the converging light to form an image for coupling into the waveguide such that the light propagates through the waveguide to form an image in the user's eye; and

a fixed aperture mask positioned between the digital dynamic hologram and the waveguide and configured to block converging light from the light source that is not diffracted by the digital dynamic hologram.

19. The near-eye display device ofclaim 18, further comprising a pupil replicating hologram coupled with the waveguide and configured to receive light reflected by the digital dynamic hologram and direct the received light toward the user's eye.

20. The near-eye display device ofclaim 18, wherein the fixed aperture mask is further configured to block one or more orders of diffracted light received from the digital dynamic hologram.

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